DE102004029429B4 - Components for high frequency technology - Google Patents

Abstract

worin
C_nH_2n+1 geradkettige Alkylreste mit n C-Atomen bedeuten,
enthält.

Controllable component for high-frequency applications, characterized in that it contains as controllable medium a liquid crystal material whose phase shift quality and / or Marterialgüte is 10% or more greater than the corresponding value of an otherwise identical device with K15 and in that the liquid crystal material is a liquid crystal mixture containing one or more compounds with terminal -NCS group selected from the group of compounds

wherein
C _n H _{2n + 1} denote straight-chain alkyl radicals with n C atoms,
contains.

Description

Present invention

The present invention relates to components for high frequency technology, and for the microwave technology, in particular microwave components. It particularly relates to controllable components, preferably microwave components, which use liquid crystals, preferably nematic liquid crystals, as controllable dielectrics. Particularly preferred are passively controllable components. In addition, the present invention relates to the liquid crystal materials used in these elements, as well as their use in the elements, as well as a method for producing the corresponding components.

Technical area

Analogous, passively controllable microwave components can be realized with the help of nonlinear dielectrics. Nonlinear dielectrics are materials whose dielectric constant ε _r depends strongly on the effective electric field strength in the material. The internal electrical polarization can be changed as a function of an external electric field or an applied electrical voltage.

For a long time, great research efforts have been made in the field of integration of passively controllable microwave components with ferroelectrics [Wol1]. In the present application, the references are given in abbreviated form as above. The abbreviations used are listed in a separate table.

So far, epitaxial thin-film technology has been used on single-crystalline substrate materials such as MgO or LaAlO ₃ [Cha2], [Gev6], [Sen3], [Var2], [Yor1]. Research efforts focused on the optimization of thin films deposited on high-purity, monocrystalline substrates by means of chemical (eg MOCVD) or physical (eg PLD) or RF sputtering techniques, as well as the realization and optimization of controllable microwave devices such as varactors and crystallographic devices Phase shifters for phased-array antennas [Aci1], [Aci2], [Bab1], [Car3], [DeF1], [Erk1], [Kir1], [Koz1], [Liu1], [Rao1], [Rom1], [Rom2 ], [Sen5], [She1], [Sub3], [Sub4], [Van3], [Var1], [Var3], [Wil1].

With high-purity Ba _x Sr _1-x TiO ₃ - (BST) thin films on MgO substrates in [Car3] at 31.34 GHz was a phase shift (also called figure of merit, "FoM") between about 30 ° / dB and 45 ° / dB demonstrated at room temperature. The FoM is defined as the quotient of differential phase shift with and without control voltage with respect to the insertion losses of the device. With coplanar "loaded-line" phase shifters using interdigital capacitors and plate capacitors with BST thin films, even in the X-band (frequency range around 10 GHz) phase shift transients of 50 ° / dB to 80 ° / dB have been achieved [Aci1], [ Aci2].

Other approaches focus primarily on fine-grained ceramic thick films of ferroelectric material systems in conjunction with high purity Al ₂ O ₃ substrates. Here, material systems for room temperature applications such as Ba _x Sr _1-x TiO ₃ and BaZr _y Ti _1-y O _{3 are} in the foreground. In this context, uniplanar circuits with components such as interdigital capacitors and coplanar lines are used. With the coplanar line arrangement presented in [Weil3] on a thin ferroelectric thick film, a phase shift of 28 ° / dB at 24 GHz and approx. 300 V control voltage (control field strength 10V / μm) was achieved. As a major loss mechanism that contributes to the reduction of the phase shift, the dielectric losses of the ferroelectric layer are called.

As an alternative to ferroelectrics, there are publications of components which use liquid crystals (LCs for short: liquid crystals) as a controllable dielectric. Liquid crystals are primarily used in optical liquid crystal displays (LCs) [Fin1], optical switches or amplitude modulators [Chi1]. Here, one makes use of the effect of the anisotropy of the optical refractive indices (birefringence). However, the anisotropy of the liquid crystal also affects the dielectric properties, with the microwave behavior of nematic LCs still under research. So far, however, in comparison to the optical properties, in particular the anisotropy in the high frequency range, especially in the microwave range and the corresponding losses are still largely unknown.

As a typical microwell application, the concept of the inverted microstrip line [Gup2] becomes, for example, in [Dol1], [Mar1], [Weil1], [Weil2] together with the commercial liquid crystal K15 the company Merck KGaA used. [Weil2] achieves phase shift tolerances of 12 ° / dB at 10 GHz with approx. 40 V control voltage. The insertion losses of the LC, ie the losses which are only due to the polarization losses in the liquid crystal, are given in [Weil1] at approximately 1 to 2 dB at 10 GHz. In addition, it was determined that the phase shifter losses are primarily determined by the dielectric LC losses and the losses at the waveguide junctions used there. [Kuk1] and [Kuk2] also address the use of polymerized LC films and dual-frequency switching-mode liquid crystals in conjunction with planar phase shifter assemblies.

Object of the present invention

The comparison of the known liquid crystal phase shifter with phase shifters based on solid, ferroelectric thick films or thin films shows that the latter have a two to seven times lower Phasenschiebergüte and thus are hardly usable for applications in microwave technology. The low quality is in [Weil1] primarily due to the comparatively low dielectric controllability of the liquid crystalline single compound pentylcyano-biphenyl (short 5CB, in the present application K15 called) returned. Thus, there is a need for liquid crystal materials having increased controllability.

Since the LC K15 have completely unsatisfactory microwave properties, special liquid crystal compounds and complex liquid crystal mixtures were analyzed for their suitability for applications in the high frequency range, in particular their anisotropy and losses in the microwave range at 8.8 to 8.75 GHz. The investigations and their results will be described below.

DE 693 14 001 T2 discloses diphenyldiacetylenes and also suggests them for microwave applications. However, the compounds are not examined there for their suitability.

DE 699 09 436 T2 and EP 1 126 006 A2 are directed to isothiocyanate compounds. However, these are proposed only for use in liquid crystal displays.

Description of the disturbance measurement method used

As a resonator for the Störkörpermessungen a cylinder resonator is selected. The structure consists of three parts, a hollow cylinder and a lid and bottom, which complete the cylinder top and bottom. As a material is brass and the inside of the three parts was silvered and polished to keep the wall losses of the resonator as low as possible and thus to achieve a high quality. The bottom and top plates are connected with 4 screws each with the hollow cylinder wall.

• Radius α ≈ 13mm
• Höhe h ≈ 20mm

Since the dielectric material parameters of the test samples to be investigated are to be determined in the GHz range, the following internal dimensions were selected for the resonator:

• Radius α ≈ 13mm
• Height h ≈ 20mm

The coupling and decoupling of the resonator takes place at two opposite, perpendicular coupling loops, which are mounted centrally by means of a bore through the cylinder wall. The ends of the coupling loops were each connected to an inner conductor of a 3.5 mm SMA socket and to the cylinder wall. Among other things, the TM ₀₁₀ mode can be excited with this vertical coupling loop (see field line image ).

With these dimensions results for the TM ₀₁₀ mode, a resonant frequency of about 8.75 GHz for the empty resonator. Since this mode is the fundamental mode, it is easily identifiable in measurements by being the mode with the lowest resonant frequency. The course of the resonance curves of the different modes for the empty resonator is investigated in the range of 1-26 GHz. The TM ₀₁₀ mode is the marked first resonance.

Liquid crystals have a dielectric anisotropy. Due to their structure, there are different permittivities, depending on the angle between the microwave field and the director of the liquid crystal molecules. In the following, parallelism between microwave field and director is denoted by ∥ and orthogonality by ⊥. The director of liquid crystal molecules can be influenced by DC electric or magnetic fields. For the orientation of the director here a direct magnetic field was used. to Determination of full orientation measurements were made with different field strengths. If the measurements reach a saturation value, it can be assumed that a perfect orientation of the molecules prevails. For a parallel director, due to the mode image of the TM ₀₁₀ mode, a DC magnetic field must be applied from the bottom plate to the top plate. For a vertical director, a dc field is applied from one wall of the cylinder jacket to the opposite wall. For this purpose, a coil with a yoke was used. By arranging the coil around the cylinder resonator (horizontally for parallel, vertically for perpendicular), the just-described director orientations were set.

To determine the complex permittivity, the measurement of the resonance curve is required. For this purpose, a network analyzer HP 8510B from Hewlett Packard is used.

The network analyzer measures the transmission factor - up to 801 - discrete nodes over the set frequency range. shows the lateral cross section of the resonator with the centered material sample.

3.5 mm SMA sockets are screwed to the cylinder resonator on opposite sides. Thin silver wires are attached to the inner conductor of a 3.5 mm SMA socket and connected to the inner wall of the cylinder. This ensures that the TM ₀₁₀ mode to be considered is excited.

In the middle of the resonator, the material sample is introduced. This material sample slightly changes the resonance frequency compared to the measurement without a material sample. From these measurements, the material parameters ε _r and tan δ can be calculated.

To measure the liquid crystals, a Teflon tube was filled with the liquid crystal to be examined and introduced into the cylinder resonator. To increase the accuracy of the measurement, the samples should be as thin as possible, so that the field of the resonator is not changed too much and the max. E field can be assumed to be constant within the sample. However, the Teflon tubes can not be chosen arbitrarily thin. On the one hand, it limits mechanical manufacturing tolerances that the tubes can be made arbitrarily thin, on the other hand, the tubes must have a minimum diameter to stay in the resonator and not tip over.

• Außenradius b = 3mm;Wand- bzw. Bodenstärke d = 0,2 mm Höhe h = 20 mm = Resonatorhöhe.

The teflon tube used was made with the following dimensions:

• Outside radius b = 3mm, wall or floor thickness d = 0.2 mm height h = 20 mm = resonator height.

nicht überschritten wird.With this diameter the Teflon tube ensures that there is a ratio of the two radii $\frac{\text{Resonatorradius}}{\text{samples radius}}\le \mathrm{12:11}$

is not exceeded.

For each measurement, the teflon tube is placed vertically in the resonator.

It is important to ensure that the sample material is in the center of the resonator (at the maximum of the E field) and does not fall over due to vibration during the measurement. In order to place the material sample as precisely as possible in the center during the measurements, a plastic template was specially made for this purpose. This plastic template has a stop, so that the template fits only in one position in the resonator. In the middle is a hole that is so large that the teflon tube fits right through it. After carefully pulling out the template, the Teflon rouge stops in the center.

Thereafter, the resonator is closed.

Since only the TM ₀₁₀ mode is evaluated during the measurement, it is necessary to set the measuring range so that at least the -3 dB bandwidth of the TM ₀₁₀ -mode can be measured. However, for sufficient resolution of the resonance, the frequency range should not be much larger than 5 times the bandwidth of the TM ₀₁₀ mode.

When measuring the S-parameters with the network analyzer, systematic errors can occur due to the supply lines and line transitions. The leads can significantly affect the measurement by their attenuation. Therefore, calibration must be performed before each measurement.

• - Kurzschluss,
• - offener Abschluss bzw.
• - definierter Abschluss (50 Ohm).

In a calibration measurement, so-called reference objects (standards) whose behavior is clearly known are used instead of the test object. The reference objects are three defined components:

• - short circuit,
• - open degree or
• - defined degree (50 ohms).

From the difference between the measured and known behavior of these standards, the network analyzer calculates the error correction coefficients.

Furthermore, continuity measurements of the two interconnected supply lines are made for calibration.

Calibration must be performed each time a new frequency range is set on the network analyzer.

To assess the accuracy of a measurement process, it is essential to estimate its errors.

The errors in measurements are broken down into random errors and systematic errors.

In most cases, the sought-after variable is not directly measurable, but a function f = f (x, y, ..) of other measurable quantities x, y, ... and is thus calculated from these.

The quantities sought in the measurements carried out are ε ' _r and tan δ _ε , which depend on different measurable quantities in the analytical equations (1) to (3).

$${\epsilon }_r^{\text{'}\text{'}}=\mathrm{0,2695}\cdot {\left(\frac{a}{b}\right)}^2\cdot \left(\frac{1}{Q_{L2}}-\frac{1}{Q_{L1}}\right)$$

$$\text{tan}{\delta }_{\epsilon }=\frac{{\epsilon }_r^{\text{'}\text{'}}}{{\epsilon }_r^{\text{'}}}=\frac{\mathrm{0,2695}}{{\epsilon }_r^{\text{'}}}\cdot {\left(\frac{a}{b}\right)}^2\cdot \left(\frac{1}{Q_{L2}}-\frac{1}{Q_{L1}}\right)=\frac{\mathrm{0,2695}\left(\frac{1}{Q_{L2}}-\frac{1}{Q_{L1}}\right)}{\mathrm{0,539}\left(\frac{f_{r\mathrm{,1}}-f_{r\mathrm{,2}}}{f_{r\mathrm{,2}}}\right)+{\left(\frac{b}{a}\right)}^2}$$

To determine the material parameters, the following formulas are used according to [Par]: $$\epsilon {\text{'}}_r=0.539\cdot {\left(\frac{a}{b}\right)}^2\cdot \left(\frac{f_{r\mathrm{,1}}-f_{r2}}{f_{r2}}\right)+1$$

$${\epsilon }_r^{\text{'}\text{'}}=.2695\cdot {\left(\frac{a}{b}\right)}^2\cdot \left(\frac{1}{Q_{L2}}-\frac{1}{Q_{L1}}\right)$$

$$\text{tan}{\delta }_{\epsilon }=\frac{{\epsilon }_r^{\text{'}\text{'}}}{{\epsilon }_r^{\text{'}}}=\frac{.2695}{{\epsilon }_r^{\text{'}}}\cdot {\left(\frac{a}{b}\right)}^2\cdot \left(\frac{1}{Q_{L2}}-\frac{1}{Q_{L1}}\right)=\frac{.2695\left(\frac{1}{Q_{L2}}-\frac{1}{Q_{L1}}\right)}{0.539\left(\frac{f_{r\mathrm{,1}}-f_{r2}}{f_{r2}}\right)+{\left(\frac{b}{a}\right)}^2}$$

In order to extract the dielectric parameters of the liquid crystals in the teflon tube, the formulas for extraction must be modified, the measured values (ε ', ε ") being interpreted as effective values (equation (4)).

Due to the very small volume of the bottom of the Teflon sleeve, its influence on the calculation formulas was neglected. The Teflon wall and filled liquid was considered to be a parallel connection of two axially layered dielectrics.

mit $$\begin{array}{l}\frac{A_1}{A_{ges}}=K_1\text{ und }\frac{A_2}{A_{ges}}=K_2\text{ folgt}\hfill \\ {\epsilon }_{eff}^{\text{'}}-j{\epsilon }_{eff}^{\text{'}\text{'}}=\left({\epsilon }_1^{\text{'}}{K}_1+{\epsilon }_2^{\text{'}}{K}_2\right)-j\left({\epsilon }_1^{\text{'}\text{'}}{K}_1+{\epsilon }_2^{\text{'}\text{'}}{K}_2\right)\hfill \end{array}$$

The splitting of two parallel-connected dielectric materials, which are in a constant E field, is done according to the following equations, which were obtained from the equation for the parallel connection of capacitors: $${\underset{\_}{\epsilon }}_r{A}_r\to {\underset{\_}{\epsilon }}_{eff}{A}_{Ges}={\underset{\_}{\epsilon }}_1{\mathrm{<figure-callout\; id="1"\; label="A"\; filenames="DE102004029429B4\_0086.png"\; state="\{\{state\}\}">A</figure-callout>}}_1+{\underset{\_}{\epsilon }}_2{A}_2$$

With $$\begin{array}{l}\frac{A_1}{A_{Ges}}={\mathrm{<figure-callout\; id="1"\; label="K"\; filenames="DE102004029429B4\_0086.png"\; state="\{\{state\}\}">K</figure-callout>}}_1\text{and}\frac{A_2}{A_{Ges}}=K_2\text{follows}\hfill \\ {\epsilon }_{eff}^{\text{'}}-j{\epsilon }_{eff}^{\text{'}\text{'}}=\left({\epsilon }_1^{\text{'}}{\mathrm{<figure-callout\; id="1"\; label="K"\; filenames="DE102004029429B4\_0086.png"\; state="\{\{state\}\}">K</figure-callout>}}_1+{\epsilon }_2^{\text{'}}{K}_2\right)-j\left({\epsilon }_1^{\text{'}\text{'}}{\mathrm{<figure-callout\; id="1"\; label="K"\; filenames="DE102004029429B4\_0086.png"\; state="\{\{state\}\}">K</figure-callout>}}_1+{\epsilon }_2^{\text{'}\text{'}}{K}_2\right)\hfill \end{array}$$

$$\text{tan }{\delta }_{{\epsilon }_1}=\frac{{\epsilon }_1^{\text{'}\text{'}}}{{\epsilon }_1^{\text{'}}}=\frac{{\epsilon }_{eff}^{\text{'}\text{'}}-{\epsilon }_2^{\text{'}\text{'}}{K}_2}{{\epsilon }_{eff}^{\text{'}}-{\epsilon }_2^{\text{'}}{K}_2}$$

Separated into real and imaginary parts, the result is resolved to ε ' ₁ and ε " ₁ : $${\epsilon }_1^{\text{'}}=\frac{{\epsilon }_{eff}^{\text{'}}-{\epsilon }_2^{\text{'}}{K}_2}{{\mathrm{<figure-callout\; id="1"\; label="K"\; filenames="DE102004029429B4\_0086.png"\; state="\{\{state\}\}">K</figure-callout>}}_1}\text{and}{\epsilon }_1^{\text{'}\text{'}}=\frac{{\epsilon }_{eff}^{\text{'}\text{'}}-{\epsilon }_2^{\text{'}\text{'}}{K}_2}{{\mathrm{<figure-callout\; id="1"\; label="K"\; filenames="DE102004029429B4\_0086.png"\; state="\{\{state\}\}">K</figure-callout>}}_1}$$

$$\text{<figure-callout id="1" label="tan δ ε" filenames="DE102004029429B4\_0086.png" state="{{state}}">tan </figure-callout>}{\delta }_{{\epsilon }_{}}{{}_1}_{}=\frac{{\epsilon }_1^{\text{'}\text{'}}}{{\epsilon }_1^{\text{'}}}=\frac{{\epsilon }_{eff}^{\text{'}\text{'}}-{\epsilon }_2^{\text{'}\text{'}}{K}_2}{{\epsilon }_{eff}^{\text{'}}-{\epsilon }_2^{\text{'}}{K}_2}$$

• A₁ ist die Zylindergrundfläche der Flüssigkeitssäule: (b-d)² · π
• A₂ ist die ringförmige Grundfläche der Teflonhülse: (b² - (b - d)²)· π
• A_ges ist die gesamte Grundfläche des Zylinderröhrchens: b²π

Where ε ' ₂ and ε " _{2 are} the material constants for the teflon tube (known) and ε' ₁ and ε" ₁ that of the filled liquid (sought).

• A ₁ is the cylinder base area of the liquid column: (bd) ² · π
• A ₂ is the annular base of the Teflon sleeve: (b ² - (b - d) ² ) · π
• A _ges is the total base area of the cylinder tube: b ² π

The liquids were filled in the measurements with a glass pipette in the Teflon tube. Always make sure that no air bubbles are trapped in the tube. Also pay attention to the exact centering of the sample in the resonator.

The literature value of [Riz] was used for the material constants for the Teflon sleeve:
ε '= 2.05; tan δ _ε = 0.00015

In order to be able to estimate how large the maximum error limits are, the maximum error consideration (complete differential) should be used for the further error calculation of the measurement results. The formula for the worst-case or maximum error was: $$\Delta f=\pm \left(\left|\frac{\partial f}{\partial x}\right|\Delta x+\left|\frac{\partial f}{\partial y}\right|\Delta y+...\right)$$

Here, Δf is the maximum error; x, y, ... are the error-prone magnitudes and Δx, Δy, .... are the deviations of the magnitudes x, y, ....

$$\Delta {\epsilon }_r^{\text{'}}=\left|\frac{\partial {\epsilon }_r^{\text{'}}}{\partial a}\right|\Delta a+\left|\frac{\partial {\epsilon }_r^{\text{'}}}{\partial b}\right|\Delta b+\left|\frac{\partial {\epsilon }_r^{\text{'}}}{\partial f_{r\mathrm{,1}}}\right|\Delta f_{r\mathrm{,1}}+\left|\frac{\partial {\epsilon }_r^{\text{'}}}{\partial f_{r\mathrm{,2}}}\right|\Delta f_{r\mathrm{,2}}$$

$$\begin{array}{c}\Delta {\epsilon }_r^{\text{'}}=\left|\mathrm{0,539}\left(\frac{f_{r\mathrm{,1}}-f_{r\mathrm{,2}}}{f_{r\mathrm{,2}}}\right)\frac{2a}{b^2}\right|\Delta \text{a}+\left|\mathrm{0,539}\left(\frac{f_{r\mathrm{,1}}-f_{r\mathrm{,2}}}{f_{r\mathrm{,2}}}\right)\frac{\left(-2\right)a^2}{b^3}\right|\Delta b+\left|\mathrm{0,539}{\left(\frac{a}{b}\right)}^2\left(\frac{1}{f_{r\mathrm{,2}}}\right)\right|\Delta f_{r\mathrm{,1}}\\ +\left|\mathrm{0,539}{\left(\frac{a}{b}\right)}^2\left(-1\right)\left(\frac{f_{r\mathrm{,1}}}{f_{r\mathrm{,2}}{}^2}\right)\right|\Delta f_{r\mathrm{,2}}\end{array}$$

$$\text{tan}{\delta }_{\epsilon }=\frac{\mathrm{0,2695}}{{\epsilon }_r^{\text{'}}}{\left(\frac{a}{b}\right)}^2\left(\frac{1}{Q_{L2}}-\frac{1}{Q_{L1}}\right)$$

$$\Delta \text{tan}{\delta }_{\epsilon }=\left|\frac{\partial \text{tan}{\delta }_{\epsilon }}{\partial {\epsilon }_r^{\text{'}}}\right|\Delta {\epsilon }_r^{\text{'}}+\left|\frac{\partial \text{tan}{\delta }_{\epsilon }}{\partial a}\right|\Delta a+\left|\frac{\partial \text{tan}{\delta }_{\epsilon }}{\partial b}\right|\Delta b+\left|\frac{\partial \text{tan}{\delta }_{\epsilon }}{\partial Q_{L2}}\right|\Delta Q_{L2}+\left|\frac{\partial \text{tan}{\delta }_{\epsilon }}{\partial Q_{L1}}\right|\Delta Q_{L1}$$

$$\begin{array}{ll}\Delta \text{tan}{\delta }_{\epsilon }\hfill & =\left|-\frac{\mathrm{0,2695}}{{\epsilon }_r^{\text{'}2}}{\left(\frac{a}{b}\right)}^2\left(\frac{1}{Q_{L2}}-\frac{1}{Q_{L1}}\right)\right|\Delta {\epsilon }_r^{\text{'}}+\left|\frac{2\cdot \mathrm{0,2695}}{{\epsilon }_r^{\text{'}}}\frac{a}{b^2}\left(\frac{1}{Q_{L2}}-\frac{1}{Q_{L1}}\right)\right|\Delta a\hfill \\ \hfill & +\left|\frac{\left(-2\right)\cdot \mathrm{0,2695}}{{\epsilon }_r^{\text{'}}}\frac{a^2}{b^3}\left(\frac{1}{Q_{L2}}-\frac{1}{Q_{L1}}\right)\right|\Delta b+\left|\frac{-\mathrm{0,2695}}{{\epsilon }_r^{\text{'}}}{\left(\frac{a}{b}\right)}^2\left(\frac{1}{Q_{L2}{}^2}\right)\right|\Delta Q_{L2}\hfill \\ \hfill & +\left|\frac{\mathrm{0,2695}}{{\epsilon }_r^{\text{'}}}{\left(\frac{a}{b}\right)}^2\left(\frac{1}{Q_{L1}{}^2}\right)\right|\Delta Q_{L1}\hfill \end{array}$$

Applying this formula to equations (2) and (3) to determine the maximum error yields the following expressions: $$\epsilon {\text{'}}_r=0.539\cdot {\left(\frac{a}{b}\right)}^2\cdot \left(\frac{f_{r\mathrm{,1}}-f_{r2}}{f_{r2}}\right)+1$$

$$\Delta {\epsilon }_r^{\text{'}}=\left|\frac{\partial {\epsilon }_r^{\text{'}}}{\partial a}\right|\Delta a+\left|\frac{\partial {\epsilon }_r^{\text{'}}}{\partial b}\right|\Delta b+\left|\frac{\partial {\epsilon }_r^{\text{'}}}{\partial f_{r\mathrm{,1}}}\right|\Delta f_{r\mathrm{,1}}+\left|\frac{\partial {\epsilon }_r^{\text{'}}}{\partial f_{r2}}\right|\Delta f_{r2}$$

$$\begin{array}{c}\Delta {\epsilon }_r^{\text{'}}=\left|0.539\left(\frac{f_{r\mathrm{,1}}-f_{r2}}{f_{r2}}\right)\frac{2a}{b^2}\right|\Delta \text{a}+\left|0.539\left(\frac{f_{r\mathrm{,1}}-f_{r2}}{f_{r2}}\right)\frac{\left(-2\right)a^2}{b^3}\right|\Delta b+\left|0.539{\left(\frac{a}{b}\right)}^2\left(\frac{1}{f_{r2}}\right)\right|\Delta f_{r\mathrm{,1}}\\ +\left|0.539{\left(\frac{a}{b}\right)}^2\left(-1\right)\left(\frac{f_{r\mathrm{,1}}}{f_{r2}{}^2}\right)\right|\Delta f_{r2}\end{array}$$

$$\text{tan}{\delta }_{\epsilon }=\frac{.2695}{{\epsilon }_r^{\text{'}}}{\left(\frac{a}{b}\right)}^2\left(\frac{1}{Q_{L2}}-\frac{1}{Q_{L1}}\right)$$

$$\Delta \text{tan}{\delta }_{\epsilon }=\left|\frac{\partial \text{tan}{\delta }_{\epsilon }}{\partial {\epsilon }_r^{\text{'}}}\right|\Delta {\epsilon }_r^{\text{'}}+\left|\frac{\partial \text{tan}{\delta }_{\epsilon }}{\partial a}\right|\Delta a+\left|\frac{\partial \text{tan}{\delta }_{\epsilon }}{\partial b}\right|\Delta b+\left|\frac{\partial \text{tan}{\delta }_{\epsilon }}{\partial Q_{L2}}\right|\Delta Q_{L2}+\left|\frac{\partial \text{tan}{\delta }_{\epsilon }}{\partial {\mathrm{<figure-callout\; id="1"\; label="Q\; L"\; filenames="DE102004029429B4\_0086.png"\; state="\{\{state\}\}">Q\; </figure-callout>}}_L}\right|\mathrm{<figure-callout\; id="1"\; label="\Delta \; Q\; L"\; filenames="DE102004029429B4\_0086.png"\; state="\{\{state\}\}">\Delta \; </figure-callout>}{Q}_L{1}_{}$$

$$\begin{array}{ll}\Delta \text{tan}{\delta }_{\epsilon }\hfill & =\left|-\frac{.2695}{{\epsilon }_r^{\text{'}2}}{\left(\frac{a}{b}\right)}^2\left(\frac{1}{Q_{L2}}-\frac{1}{Q_{L1}}\right)\right|\Delta {\epsilon }_r^{\text{'}}+\left|\frac{2\cdot .2695}{{\epsilon }_r^{\text{'}}}\frac{a}{b^2}\left(\frac{1}{Q_{L2}}-\frac{1}{Q_{L1}}\right)\right|\Delta a\hfill \\ \hfill & +\left|\frac{\left(-2\right)\cdot .2695}{{\epsilon }_r^{\text{'}}}\frac{a^2}{b^3}\left(\frac{1}{Q_{L2}}-\frac{1}{Q_{L1}}\right)\right|\Delta b+\left|\frac{-.2695}{{\epsilon }_r^{\text{'}}}{\left(\frac{a}{b}\right)}^2\left(\frac{1}{Q_{L2}{}^2}\right)\right|\Delta Q_{L2}\hfill \\ \hfill & +\left|\frac{.2695}{{\epsilon }_r^{\text{'}}}{\left(\frac{a}{b}\right)}^2\left(\frac{1}{{\mathrm{<figure-callout\; id="1"\; label="Q\; L"\; filenames="DE102004029429B4\_0086.png"\; state="\{\{state\}\}">Q\; </figure-callout>}}_L{}^2}\right)\right|\mathrm{<figure-callout\; id="1"\; label="\Delta \; Q\; L"\; filenames="DE102004029429B4\_0086.png"\; state="\{\{state\}\}">\Delta \; </figure-callout>}{Q}_L{1}_{}\hfill \end{array}$$

These equations were used to determine the maximum errors of the sample or sample tube tested with filling.

Present invention

worin
C_nH_2n+1 geradkettige Alkylreste mit n C-Atomen bedeuten, enthalten.The present invention provides improved components for the high-frequency range, characterized in that the liquid-crystal media used have a phase shift quality and / or a material quality that is 10% or more greater than the corresponding value of an otherwise identical component with the individual substance K15 and that one or more compounds containing terminal -NCS group selected from the group of compounds of the formulas

wherein
C _n H _{2n + 1} straight-chain alkyl radicals with n C atoms mean, included.

Description of preferred embodiments

Preferred devices are phase shifters, varactors, radio and radio wave antenna arrays, and others

In the present application, unless expressly stated otherwise, the term compounds means both one compound and several compounds.

The liquid-crystal media used in the components according to the invention preferably have nematic phases of in each case at least from -20.degree. C. to 80.degree. C., preferably from -30.degree. C. to 85.degree. C. and very particularly preferably from -40.degree. C. to 100.degree. More preferably, the phase is up to 120 ° C or more, preferably up to 140 ° C or more, and most preferably up to 180 ° C or more. In this case, the term "nematic phase" means, on the one hand, that no smectic phase and no crystallization are observed at low temperatures at the corresponding temperature and, on the other hand, that clarification does not yet occur on heating from the nematic phase. The investigation at low temperatures is carried out in a flow viscometer at the appropriate temperature and checked by storage in test cells, with a layer thickness of 5 microns, for at least 100 hours. At high temperatures, the clearing point is measured in capillaries by conventional methods.

Furthermore, the liquid-crystal media used in the components according to the invention are characterized by high visual anisotropies in the visible range. The birefringence at 589 nm is preferably 0.20 or more, particularly preferably 0.25 or more, particularly preferably 0.30 or more, particularly preferably 0.40 or more and very particularly preferably 0.45 or more. In addition, the birefringence is preferably 0.80 or less.

Furthermore, the liquid-crystal media used in the components according to the invention are characterized by high optical anisotropies in the microwave range. The birefringence is e.g. at about 8.3 GHz preferably 0.14 or more, more preferably 0.15 or more, more preferably 0.20 or more, more preferably 0.25 or more, and most preferably 0.30 or more. In addition, the birefringence is preferably 0.80 or less.

The liquid crystal materials preferably used in the components according to the invention have phase shift transmittances of 15 ° / dB or more, preferably 20 ° / dB or more, preferably 30 ° / dB or more, preferably 40 ° / dB or more, preferably 50 ° / dB or more, more preferably 80 ° / dB or more and most preferably 100 ° / dB or more.

The material quality Δn (μ-waves) / tan (δ) of the liquid crystal materials preferably used in the components according to the invention is 3 or more, preferred 4 or more, preferred 5 or more, preferred 10 or more, preferred 15 or more, preferred 17 or more, more preferably 20 or more and most preferably 25 or more.

The applied liquid crystals preferably have a positive dielectric anisotropy. This is preferably 5 or greater, preferably 10 or greater, more preferably 20 or larger and most preferably 30 or larger.

However, in some embodiments, liquid crystals having a negative dielectric anisotropy may also be used to advantage.

The liquid crystals used are individual substances or mixtures. Preferably, they have a nematic phase.

The individual liquid-crystal compounds are selected essentially from the known compounds, or are obtainable analogously to known compounds.

Preference is given to using compounds or mixtures of compounds, the compounds generally containing two, three or four multi-membered, preferably five- or six-membered, particularly preferably six-membered, rings. However, the compounds may also contain multi-membered rings and / or annelated rings, preferably bivalent naphthalenes or phenanthrenes. Particular preference is given to compounds which contain rings, preferably 1,4-phenylene rings, which are optionally monosubstituted or polysubstituted. The rings are preferably laterally substituted by halogen (especially F, Cl) but also by pseudohalides. The aromatic rings may optionally be heterocyclic, in particular N-heterocyclic rings, preferably bivalent pyridine or pyrimidine. It is also possible to use compounds with bivalent cyclohexyl, dioxane, tetrahydropyran, thiazole, thiadiazole, oxazole or oxadiazole rings. In at least one of the terminal positions is at least some compounds contained in the mixtures used, a polar end group, preferably NCS, CN, SCN, NCO, halogen, bev. F or Cl is a pseudohalide, a partially or completely fluorinated alkyl alkoxy, alkenyl or alkenyloxy group, wherein one or more, preferably usually not adjacent, CH ₂ groups by O, S and / or C = O, replaced preferably OCF ₃ , CF ₃ , and also mean SF ₅ or SO ₂ CF ₃ . The other terminal position may also contain a substituent from the last-mentioned group of the dielectrically positive substituents, but it may be a dielectrically neutral group such. And preferably alkyl, alkenyl, alkoxy, alkenyloxy or oxaalkyl.

If liquid-crystalline mixtures are used, these usually also contain dielectrically neutral compounds in which both ends of the molecule preferably, independently of one another, carry one of the last-mentioned dielectrically neutral groups.

The usually bivalent rings of the molecules can be directly connected to each other. However, it could also be linked by bridges. The compounds preferably contain no one or two, more preferably none or one bridging group. Preferably, they contain a bridge with an even number of bridge atoms. Preferably -C = CH-, -C = C-, -CO-O-, -O-CO-, -CF ₂ O- or -O-CF ₂ -.

The term "alkyl" preferably includes straight-chain and branched alkyl groups having 1 to 7 carbon atoms, in particular the straight-chain groups methyl, ethyl, propyl, butyl, pentyl, hexyl and heptyl. Groups of 2 to 5 carbon atoms are generally preferred.

The term "alkenyl" preferably includes straight-chain and branched alkenyl groups 2 to 7 Carbon atoms, in particular the straight-chain groups. Particularly preferred alkenyl groups are C ₂ to C ₇ -1E-alkenyl, C ₄ to C ₇ -3E-alkenyl, C ₅ to C ₇ -4-alkenyl, C ₆ to C ₇ -5-alkenyl and C ₇ -6-alkenyl , in particular C ₂ to C ₇ -1E-alkenyl, C ₄ to C ₇ -3E-alkenyl and C ₅ to C ₇ -4-alkenyl. Examples of further preferred alkenyl groups are vinyl, 1E-propenyl, 1E-butenyl, 1E-pentenyl, 1E-hexenyl, 1E-heptenyl, 3-butenyl, 3E-pentenyl, 3E-hexenyl, 3E-heptenyl, 4-pentenyl, 4Z-hexenyl , 4E-hexenyl, 4Z-heptenyl, 5-hexenyl, 6-heptenyl and the like. Groups of up to 5 carbon atoms are generally preferred.

The term "fluoroalkyl" preferably includes straight-chain fluoro-end-capped groups, i. Fluoromethyl, 2-fluoroethyl, 3-fluoropropyl, 4-fluorobutyl, 5-fluoropentyl, 6-fluorohexyl and 7-fluoroheptyl. Other positions of the fluorine are not excluded.

The term "oxaalkyl" or alkoxyalkyl preferably comprises straight-chain radicals of the formula C _n H _{2n + 1} -O- (CH ₂ ) _m in which n and m are each independently of one another from 1 to 6. Preferably, n is 1 and m is 1 to 6.

Vinyl-terminated compounds and compounds having a methyl end group have low rotational viscosity.

In the present application, the terms dielectrically positive compounds mean those compounds with a Δε> 1.5, dielectrically neutral compounds those with -1.5 ≦ Δε ≦ 1.5 and dielectrically negative compounds those with Δε <-1.5. Here, the dielectric anisotropy of the compounds is determined by 10% of the compounds are dissolved in a liquid crystalline host and the capacity of at least one test cell in each case with about 20 micron layer thickness is determined with homeotropic and homogeneous surface orientation at 1 kHz. The measuring voltage is typically 0.5 V to 1.0 V, but always less than the capacitive threshold of the respective liquid-crystal mixture.

As a host mixture for the determination of the application-relevant physical parameters, ZLI-4792, from Merck KGaA, Germany, is used. As an exception, the determination of the dielectric anisotropy of dielectrically negative compounds ZLI-2857, also by Merck KGaA, Germany, is used. From the change in the properties, for example the dielectric constant, the host mixture after addition of the compound to be investigated and extrapolation to 100% of the compound used, the values for the respective compound to be investigated are obtained.

The concentration of the compound to be tested is 10%. If the solubility of the compound to be tested is insufficient for this purpose, exceptionally, the concentration used is halved, ie reduced to 5%, 2.5%, etc., until the solubility limit has fallen below.

In the present application, high-frequency technology and ultra-high frequency technology mean applications with frequencies in the range of 1 MHz to 1 THz, preferably from .1 GHz to 500 GHz, preferably 2 GHz to 300 GHz, particularly preferably from about 5 GHz to 150 GHz.

All concentrations in this application, unless explicitly stated otherwise, are given in percentage by weight and refer to the corresponding total mixture. All physical properties are and have been determined according to "Merck Liquid Crystals, Physical Properties of Liquid Crystals", Status Nov. 1997, Merck KGaA, Germany and are valid for a temperature of 20 ° C, unless explicitly stated otherwise. Δn is determined at 589 nm and Δε at 1 kHz.

In the case of the liquid-crystal media with negative dielectric anisotropy, the threshold voltage was determined as capacitive swelling Vo in cells having a lecithin homeotropically oriented liquid-crystal layer.

If necessary, the liquid-crystal media used in the components according to the invention may also contain further additives and optionally also chiral dopants in the customary amounts. The amount of these additives used is in total 0% to 10%, based on the amount of the total mixture, preferably 0.1% to 6%. The concentrations of the individual compounds used are each preferably 0.1% to 3%. The concentration of these and similar additives is not taken into account in the indication of the concentrations and the concentration ranges of the liquid crystal compounds in the liquid-crystal media.

The compositions consist of several compounds, preferably from 3 to 30, more preferably from 6 to 20 and most preferably from 10 to 16 compounds which are mixed in a conventional manner. In general, the desired amount of the components used in a lesser amount is dissolved in the components making up the main component, advantageously at elevated temperature. If the selected temperature is above the clearing point of the main constituent, the completion of the dissolution process is particularly easy to observe. However, it is also possible to prepare the liquid-crystal mixtures in other conventional ways, e.g. using premixes or from a so-called "multi-bottle" system.

The following examples serve to illustrate the invention without limiting it. In the examples the melting point T (C, N), the transition from the smectic (S) to the nematic (N) phase T (S, N) and clearing point T (N, I) of a liquid crystal substance in degrees Celsius are indicated. The different smectic phases are identified by suffixes.

Unless otherwise indicated, the percentages are by mass and percent by mass and the physical properties are those at 20 ° C unless explicitly stated otherwise.

All values given for temperatures in this application are ° C and all temperature differences are differential degrees unless explicitly stated otherwise.

In the present application and in the following examples, the structures of the liquid crystal compounds are indicated by abbreviations, also called acronyms, wherein the transformation into chemical formulas takes place in accordance with Tables A and B below. All radicals C _n H _{2n + 1} and C _m H _{2m + 1} are straight-chain alkyl radicals with n or m C atoms. The coding according to Table B is self-evident. In Table A, only the acronym for the main body is given. In individual cases, a code for the substituents R ¹ , R ² , L ¹ , L ² and L ³ follows separately from the acronym for the main body with a dash: Code for R ¹ , R ² , L ¹ , L ² , L ³ R ¹ R ² L ¹ L ² L ³ nm C _n H _{2n + 1} C _m H _{2m + 1} H H H n Om C _n H _{2n + 1} OC _m H _{2m + 1} H H H nO.m OC _n H _{2n + 1} C _m H _{2m + 1} H H H nmFF C _n H _{2n + 1} C _m H _{2m + 1} F H F nOmFF C _n H _{2n + 1} OC _m H _{2m + 1} F H F nO.mFF OC _n H _{2n + 1} C _m H _{2m + 1} F H F nO.OmFF OC _n H _{2n + 1} OC _m H _{2m + 1} F H F n C _n H _{2n + 1} CN H H H nN.F C _n H _{2n + 1} CN F H H nN.FF C _n H _{2n + 1} CN F F H nF C _n H _{2n + 1} F H H H nF.F C _n H _{2n + 1} F F H H nF.FF C _n H _{2n + 1} F F F H n Cl C _n H _{2n + 1} Cl H H H nCl.F C _n H _{2n + 1} Cl F H H nCl.FF C _n H _{2n + 1} Cl F F H NMF C _n H _{2n + 1} C _m H _{2m + 1} F H H nCF ₃ C _n H _{2n + 1} CF ₃ H H H nOCF ₃ C _n H _{2n + 1} OCF ₃ H H H nOCF ₃ .F C _n H _{2n + 1} OCF ₃ F H H nOCF ₃ .FF C _n H _{2n + 1} OCF ₃ F F H nOCF ₂ C _n H _{2n + 1} OCHF ₂ H H H nOCF ₂ .FF C _n H _{2n + 1} OCHF ₂ F F H nS C _n H _{2n + 1} NCS H H H RVSN C _r H _{2r + 1} -CH = CH-C _s H _2s - CN H H H NESN C _r H _{2r + 1} -OC _s H _2s - CN H H H nAm C _n H _{2n + 1} COOC _m H _{2m + 1} H H H nF.Cl C _n H _{2n + 1} F Cl H H Code for R ¹ , R ² , L ¹ , L ² , L ³ R ¹ R ² L ¹ L ² L ³ nS C _n H _{2n + 1} NCS H H H nS.F C _n H _{2n + 1} NCS F H H nS.FF C _n H _{2n + 1} NCS F F H

Examples

The following examples are intended to illustrate the invention without limiting it. Above and below, percentages are by weight. All temperatures are in degrees Celsius. Mp means melting point, bp. Clearing point. Furthermore, K = crystalline state, N = nematic phase, S = smectic phase and I = isotropic phase. The data between these symbols represent the transition temperatures. Δn means optical anisotropy (589 nm, 20 ° C).

Comparative Example 1

K15 was tested at 27.5 ° C for microwave properties as described in the Bluff Measurement Procedure section.

Dielectric properties of the liquid crystal were determined by aligning the director of the LC with a magnetic field up to 0.15 T parallel and perpendicular to the microwave measurement field. The data are given in the table according to Example 5.

The material grade was 2.5.

example 1

A binary mixture of 10% PVPU 3-S and 90% K15 (hereinafter called mixture A-1) was as in Comparative Example 1 describe, at 26.5 ° C, examined.

The material grade was 3.7.

Example 2

A binary mix of 20% PPTU 4-S and 80% K15 (hereinafter called mixture A-2) was as in Comparative Example 1 describe, at 26.5 ° C, examined.

The material grade was 5.1.

Example 3, Mixture M 1

composition Physical Properties connection Conc. / Mass% T (N, I) = 149.0 ° C # abbreviation 1 PGIP-3-N 4.0 n _e (20 ° C, 589 nm) = 1.9487 2 CPU-4-S 6.0 Δn (20 ° C, 589 nm) = .4083 3 PVG-2O-S 8.0 4 PVG-4O-S 8.0 ε _∥ (20 ° C, 1 kHz) = 27.0 5 PVG-5-S 10.0 Δε (20 ° C, 1 kHz) = +21.8 6 BCH 2S.F.F 13.0 7 BCH 5S.F.F 13.0 8th PTG-3-S 4.0 9 PTU-3-S 11.0 11 CPVP-3-N 5.0 12 PTP-3-S 3.0 13 PMP-4-N 3.0 14 PTPG-2-N 4.0 15 UTPP-4-S 8.0 Σ 100.0

Example 4, M 2 mixture

composition Physical Properties connection Conc. / Mass% T (N, I) = 164.5 ° C # abbreviation 1 PPU-3-S 9.0 n _e (20 ° C, 589 nm) = 1.9332 2 PPU-4-S 8.0 Δn (20 ° C, 589 nm) = .3907 3 PPU-5-S 5.0 4 BCH 4S.F.F 12.0 ε _∥ (20 ° C, 1 kHz) = 24.3 5 BCH 5S.F.F 12.0 Δε (20 ° C, 1 kHz) = +19.9 6 PNP-5-N 5.0 7 K15 5.0 8th PPYP-4N 7.0 9 PGIP-3-N 6.0 11 PGIP-4-S 5.0 12 PVG-4-S 7.0 13 PVG-5-S 8.0 14 P (1) VP-N-S 5.0 15 PVPU-3-S 6.0 Σ 100.0

Example 5, M 3 mixture

composition Physical Properties connection Conc. / Mass% T (N, I) = 143.5 ° C # abbreviation 1 PGIP-3-N 9.0 n _e (20 ° C, 589 nm) = 1.9320 2 PVG-2O-S 9.0 Δn (20 ° C, 589 nm) = .3934 3 PVG-4O-S 8.0 4 PVG-5-S 10.0 ε _∥ (20 ° C, 1 kHz) = 27.0 5 BCH 2S.F.F 10.0 Δε (20 ° C, 1 kHz) = +22.2 6 BCH 4S.F.F 13.0 7 BCH 5S.F.F 13.0 8th PTG-3-S 4.0 9 PTG-5-S 4.0 11 PTU-3-S 11.0 12 CPVP-3-N 6.0 13 PMP-4-N 4.0 14 PTPG-2-N 4.0 Σ 100.0

The mixtures of Examples 3 to 5 (M1 to M3) were investigated at a temperature of 27.5 ° C. The results are summarized in the following table.

Table of results

Example: V1 1 2 3 4 5 LC A-0 (K5) A-1 A-2 M1 M2 M3 c (K15) /% 100 90 80 deleted T / ° C 27.5 26.5 +/- 0.5 27.5 +/- 1.0 .DELTA.n (589nm) .4083 0.3907 0.3934 Freq. / GHz 8,3 ... 8,75 ε (= 0 V) 2.8291 2.8035 2.8493 3.2190 3.0966 3.4547 tan (δ) (0) 0.0355 0.0252 0.0251 0.0158 0.0137 0.0116 ε _∥ 2.9301 3.0501 3.0267 3.6832 3.6614 3.6855 tan (δ) _∥ 0.0243 0.0178 0.0198 0.0089 0.0070 0.0085 ε _⊥ 2.5028 2.5331 2.5440 2.5597 2.5993 2.5866 tan (δ) _⊥ 0.0777 0.0433 0.0584 0.0261 0.0215 0.0276 Δn _μW .1297 .1549 .1447 .3193 .3012 .3115 tan (δ) _av. 0,051 0.03055 0.0391 0.0175 0.01425 0.01805 ε _av. 2.6452 2.7054 2.7049 2.9342 2.9533 2.9529 ε _av. / tan (δ) _av. 2.54 5.07 3.70 18.24 21.14 17.26 Dielectric constant ε _r , dielectric loss factor tan δ, calculated anisotropy in the microwave range Δn _μW = | √ε _{r par} - √ε _{r vertical} |, optical anisotropy Δn _opt , mean value of tan δ and ε _r , material quality factor Δn _μW / tan δ _medium .

It can be clearly seen that the high optical anisotropy of the new LC mixtures, in contrast to K15, was successfully transferred to the lower microwave range. The anisotropy values exceed Δn _{opt of} the mixtures M1 . M2 and M3 the value for K15 and the highest previously known value for the microwave anisotropy of a liquid crystal, Δn _MW = 0.22 at 30 GHz [Lim1], [Lim2]. The anisotropy of the mixture M2 is already exceptionally high and almost as large as the anisotropy at λ = 589 nm. The anisotropy Δn _MW already seems to converge in the lower millimeter wave range against the optical anisotropy value Δn _opt . The achieved material quality is about eight times as large as in the K15 previously used in microwave circuits.

This mixture is capable of increasing the quality of LC-based microwave phase shifters far beyond 50 ° / dB, making them competitive with the technologically complex circuits based on high-purity thin films on monocrystalline substrates and even significantly surpassing the results of phase shifts with ferroelectric thick films , In addition, the ε _{r medium is of} the same order of magnitude as in standard substrate materials for microwave circuits [Rog1], which eliminates complex adjustments of conductor geometries such as in the ferroelectric thick films (ε _r ≈ 200 ... 450).

Example 6 and Comparative Example 2

It became a phase shifter in inverted microstrip technologist with the liquid crystal mixture M1 produced. For comparison, the same phase shifter was made with K15. LC K15 M1 Freq. / GHz 10 20 10 20 Spann./V diff. Phase shift / ° 0 0 0 0 0 5 28 58 75 210 10 30 62 123 241 30 35 62 132 270

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Claims (11)

Controllable component for high-frequency applications, characterized in that it contains as controllable medium a liquid crystal material whose phase shift quality and / or Marterialgüte is 10% or more greater than the corresponding value of an otherwise identical device with K15 and in that the liquid crystal material is a liquid crystal mixture containing one or more compounds with terminal -NCS group selected from the group of compounds

in which C _n H _{2n + 1 represent} straight-chain alkyl radicals having n C atoms. Component after Claim 1 , characterized in that the birefringence of the liquid crystal material at 20 ° C and 589 nm is 0.22 or more. Component according to at least one of Claims 1 and 2 , characterized in that the birefringence of the liquid crystal material in the microwave range is 0.13 or more. Component according to at least one of Claims 1 to 3 , characterized in that the liquid crystal material comprises one or more compounds selected from the group consisting of the compounds PVG-nS, PVG-nO-S, P (1) VP-nS, PTP-nS, PTG-nS, PTU-nS, CPU-nS , PGIP-nS, PPU-nS, PVPU-nS, PPTU-nS, UTPP-nS, as in Claim 1 indicated, contains. Component after Claim 4 , characterized in that the liquid crystal material comprises one or more compounds selected from the group consisting of the compounds PVG-nS, PVG-nO-S, P (1) VP-nS, PTP-nS, PTG-nS, PTU-nS, as in Claim 1 indicated, contains. Component after Claim 4 or 5 , characterized in that the liquid crystal material comprises one or more compounds selected from the group of compounds PVPU-nS, PPTU-nS, UTPP-nS, as in Claim 1 indicated, contains. Component according to at least one of Claims 1 to 6 , characterized in that the alkyl groups of the compounds of the liquid crystal material have 1 to 7 carbon atoms. Component according to at least one of Claims 1 to 7 , characterized in that the alkyl groups of the compounds of the liquid crystal material have 2 to 5 carbon atoms. Component according to at least one of Claims 1 to 8th , characterized in that it has a phase shift of 15 ° / dB and / or a Marterialgüte of 3.5 or more. Method for operating a controllable component for high-frequency technology according to at least one of Claims 1 to 9 , characterized in that a liquid crystal material is driven, which has corresponding properties. Method for producing a controllable component for high-frequency technology, characterized in that a liquid crystal material, as in at least one of the Claims 1 to 9 claimed, is filled.

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